Immune checkpoint inhibitors have shown efficacy against metastatic triple-negative breast cancer (mTNBC) but only for PD-L1positive disease. The randomized, placebo-controlled ALICE trial (NCT03164993, 24 May 2017) evaluated the addition of atezolizumab (anti-PD-L1) to immune-stimulating chemotherapy in mTNBC. Patients received pegylated liposomal doxorubicin (PLD) and low-dose cyclophosphamide in combination with atezolizumab (atezo-chemo; n = 40) or placebo (placebo-chemo; n = 28). Primary endpoints were descriptive assessment of progression-free survival in the per-protocol population (>3 atezolizumab and >2 PLD doses; n = 59) and safety in the full analysis set (FAS; all patients starting therapy; n = 68). Adverse events leading to drug discontinuation occurred in 18% of patients in the atezo-chemo arm (7/40) and in 7% of patients in the placebo-chemo arm (2/28). Improvement in progression-free survival was indicated in the atezo-chemo arm in the per-protocol population (median 4.3 months versus 3.5 months; hazard ratio (HR) = 0.57; 95% confidence interval (CI) 0.33–0.99; log-rank P = 0.047) and in the FAS (HR = 0.56; 95% CI 0.33–0.95; P = 0.033). A numerical advantage was observed for both the PD-L1positive (n = 27; HR = 0.65; 95% CI 0.27–1.54) and PD-L1negative subgroups (n = 31; HR = 0.57, 95% CI 0.27–1.21). The progression-free proportion after 15 months was 14.7% (5/34; 95% CI 6.4–30.1%) in the atezo-chemo arm versus 0% in the placebo-chemo arm. The addition of atezolizumab to PLD/cyclophosphamide was tolerable with an indication of clinical benefit, and the findings warrant further investigation of PD1/PD-L1 blockers in combination with immunomodulatory chemotherapy.

Background: Immunotherapy with checkpoint inhibitors (CPI) targeting PD-1 or CTLA-4 has emerged as an important treatment modality for several cancer forms. In hormone receptor positive breast cancer (HR + BC), this therapeutic approach is largely unexplored. We have started a clinical trial, ICON (CA209-9FN), evaluating CPI combined with selected chemotherapy in patients with metastatic HR + BC. The tumor lymphocyte infiltration is predictive for the effect of chemotherapy in BC. In ICON, we use anthracycline, which are considered as "immunogenic" chemotherapy, and low-dose cyclophosphamide, which has been reported to counter immunosuppressive cells. Methods: ICON is a randomized exploratory phase IIb study evaluating the safety and efficacy of combining nivolumab (nivo; anti-PD-1) and ipilimumab (ipi; anti-CTLA-4) with chemotherapy in subjects with metastatic HR + BC. Primary objectives are aassessment of toxicity and progression-free survival. The trial will enrol 75 evaluable subjects, randomized 2:3 into two arms (A:B). Patients in Arm A receive only chemotherapy, i.e. pegylated liposomal doxorubicin (PLD 20 mg/m 2 intravenously every 2nd week) + cyclophosphamide (cyclo; 50 mg per day, first 2 weeks in each 4 week cycle). Patients in Arm B receive PLD + cyclo + ipilimumab (1 mg intravenously every 6th week) + nivolumab (240 mg intravenously every 2nd week). Patients in arm A will be offered ipi + nivo after disease progression. Discussion: ICON is among the first clinical trials combining chemotherapy with PD-1 and CTLA-4 blockade, and the first in BC. There is a strong preclinical rationale for exploring if anthracyclines, which are considered to induce immunogenic cell death, synergize with CPI, and for combining PD-1 and CTLA-4 blockade, as these checkpoints are important in different phases of the immune response. If the ICON trial suggests acceptable safety and provide a signal of clinical efficacy, further studies are warranted. The cross-over patients from Arm A receiving ipilimumab/ nivolumab without concomitant chemotherapy represent the first BC cohort receiving this therapy. The ICON trial includes a series of translational sub-projects addressing clinically important knowledge gaps. These studies may uncover biomarkers or mechanisms of efficacy and resistance, thereby informing the development of novel combinatory regimes and of personalised biomarker-based therapy.

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Abstract Background: Immunotherapy with checkpoint inhibitors (CI) targeting PD-1 or CTLA-4 has emerged as an important treatment modality for several cancer forms. In hormone receptor positive breast cancer (HR+ BC), this therapeutic approach is largely unexplored. We have started a clinical trial, ICON (CA209-9FN), evaluating CI combined with selected chemotherapy in patients with metastatic HR+ BC. The tumor lymphocyte infiltration is predictive for the effect of chemotherapy in BC. In ICON, we use antracyclins, which are considered as “immunogenic” chemotherapy, and low-dose cyclophosphamide, which has been reported to counter immunosuppressive cells. Methods: ICON is a randomized exploratory phase IIb study evaluating the safety and efficacy of combining nivolumab (nivo; anti-PD-1) and ipilimumab (ipi; anti-CTLA-4) with chemotherapy in subjects with metastatic HR+ BC. Primary objectives are aassessment of toxicity and progression-free survival.The trial will enrol 75 evaluable subjects, randomized 2:3 into two arms (A:B). Patients in Arm A receive only chemotherapy, i.e. pegylated liposomal doxorubicin (PLD 20mg/m2 intravenously every 2nd week) + cyclophosphamide (cyclo; 50 mg per day, first 2 weeks in each 4 week cycle). Patients in Arm B receive PLD + cyclo + ipilimumab (1mg intravenously every 6th week) + nivolumab (240mg intravenously every 2nd week). Patients in arm A will be offered ipi+nivo after disease progression. Discussion: ICON is among the first clinical trials combining chemotherapy with PD-1 and CTLA-4 blockade, and the first in BC. There is a strong preclinical rationale for exploring if antracyclins, which are considered to induce immunogenic cell death, synergize with CI, and for combining PD-1 and CTLA-4 blockade, as these checkpoints are important in different phases of the immune response. If the ICON trial suggests acceptable safety and provide a signal of clinical efficacy, further studies are warranted. The sub-cohort from Arm A receiving ipilimumab/nivolumab without concomitant chemotherapy represents the first BC cohort receiving this therapy. The ICON trial includes a series of translational sub-projects addressing clinically important knowledge gaps. These studies may uncover biomarkers or mechanisms of efficacy and resistance, thereby informing the development of novel combinatory regimes and of personalised biomarker-based therapy. Trial registration: NCT03409198, Jan 24th 2018; https://clinicaltrials.gov/ct2/show/record/NCT03409198

Abstract Background: Immunotherapy with checkpoint inhibitors (CPI) targeting PD-1 or CTLA-4 has emerged as an important treatment modality for several cancer forms. In hormone receptor positive breast cancer (HR+ BC), this therapeutic approach is largely unexplored. We have started a clinical trial, ICON (CA209-9FN), evaluating CPI combined with selected chemotherapy in patients with metastatic HR+ BC. The tumor lymphocyte infiltration is predictive for the effect of chemotherapy in BC. In ICON, we use anthracycline, which are considered as “immunogenic” chemotherapy, and low-dose cyclophosphamide, which has been reported to counter immunosuppressive cells. Methods: ICON is a randomized exploratory phase IIb study evaluating the safety and efficacy of combining nivolumab (nivo; anti-PD-1) and ipilimumab (ipi; anti-CTLA-4) with chemotherapy in subjects with metastatic HR+ BC. Primary objectives are aassessment of toxicity and progression-free survival.The trial will enrol 75 evaluable subjects, randomized 2:3 into two arms (A:B). Patients in Arm A receive only chemotherapy, i.e. pegylated liposomal doxorubicin (PLD 20mg/m2 intravenously every 2nd week) + cyclophosphamide (cyclo; 50 mg per day, first 2 weeks in each 4 week cycle). Patients in Arm B receive PLD + cyclo + ipilimumab (1mg intravenously every 6th week) + nivolumab (240mg intravenously every 2nd week). Patients in arm A will be offered ipi+nivo after disease progression. Discussion: ICON is among the first clinical trials combining chemotherapy with PD-1 and CTLA-4 blockade, and the first in BC. There is a strong preclinical rationale for exploring if anthracycline, which are considered to induce immunogenic cell death, synergize with CPI, and for combining PD-1 and CTLA-4 blockade, as these checkpoints are important in different phases of the immune response. If the ICON trial suggests acceptable safety and provide a signal of clinical efficacy, further studies are warranted. The cross-overpatients from Arm A receiving ipilimumab/nivolumab without concomitant chemotherapy represent the first BC cohort receiving this therapy. The ICON trial includes a series of translational sub-projects addressing clinically important knowledge gaps. These studies may uncover biomarkers or mechanisms of efficacy and resistance, thereby informing the development of novel combinatory regimes and of personalised biomarker-based therapy. Trial registration: NCT03409198, Jan 24th 2018; https://clinicaltrials.gov/ct2/show/record/NCT03409198